Karsoth being an undetected closet Sabik was CCP plot fail of the highest order IMO.
FW wise... open, card-carrying Sabiks are not a tolerated thing in Empire, under any circumstances. But it's always been game mechanics fail that you can say "i hate the empire" and still fly for them.
The violence and destruction aimed at the Matari pales in comparison to how the Empire deals with internal heretics.
+1
Being closet Sabik in the Empire is a constant, just out of reach death sentence for you and your entire extended family. If your family spent 1500 years working up the ladder as secret "Black Nobility" types, I don't expect anything like the Karsoth plot fail going on very often.
Amarr Sabiks in power.....more like you'd meet once every few decades with masks on for 5 minutes and vanish for another few decades. "Everything cool?" "Yes" "Ok see you in 50 years, proceed."
I imagine similar to the "Death Eaters" in Harry Potter in some ways?
Could you compare this in any way to the RL Anti-Semitic propaganda of medieval Europe and persecution of the Jews by the Catholic church?
During the Spanish Inquisition, the Catholic church certainly tried very hard to weed out, stamp out, torture and convert as many Jews as they can, all in the name of their God. Understandably, the Jews often either fled for their lives or became 'Crypto-jews' (such as Nostradamus), keeping their identity a secret.
Despite 1,500 years of persecution and a small, landless population, the Jewish nation as a whole survived. Many Jews strategically make themselves indispensable to the Royal courts and society as a whole by becoming middle class professionals such as Doctors, Lawyers, scholars, etc.
Similarly, if Karsoth had somehow placed himself in an indispensable role (perhaps with help from Blood friends), he might have managed to allay suspicions and bypass security measures for a little while, anyways.
Consider this from the perspective of the 'Jewish world conspiracy' myth ala 'Protocols of the Elders of Zion'.
The Blood Raiders are trying to occupy key positions in order to control the Empire like a giant chessboard. It might just make Karsoth's deep infiltration of the Royal court story seem a little more plausible. (In an Illuminati New World Order James Bond super villain sort of way). Hypnosis, drugs, ancient technology, sorcery, who knows what tricks Karsoth might have had up his sleeve?
The myth about the Jewish 'Blood Libel', also somewhat ties into the religious use of Blood by the Sani Sabik, although perhaps that's not relevant.
Conversely, perhaps Karsoth called it as he saw it, denounced the heresy of a capsuleer of cloned flesh being an Empress, and the Empress simply had him framed up on a charge of Sani Sabik and executed him.